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Re: 0 deck, any power to be had?
[Re: Tiger Core]
#878678
12/15/10 10:18 PM
12/15/10 10:18 PM
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Joined: Dec 2008
Posts: 1,200
UK
602heavy
pro stock
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pro stock
Joined: Dec 2008
Posts: 1,200
UK
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Thanks for posting Tiger , some interesting reading there. Can you explain some more regards piston 5mm above deck & effect on head gasket? , are you saying the piston acts as a shroud of some sort? Thanks again. 
Last edited by 602heavy; 12/15/10 10:27 PM.
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Re: 0 deck, any power to be had?
[Re: 602heavy]
#878679
12/17/10 01:51 AM
12/17/10 01:51 AM
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Joined: Oct 2010
Posts: 9
California, USA
Tiger Core
member
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member
Joined: Oct 2010
Posts: 9
California, USA
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Quote:
Thanks for posting Tiger , some interesting reading there.
Can you explain some more regards piston 5mm above deck & effect on head gasket? , are you saying the piston acts as a shroud of some sort?
Thanks again.
Hello fellow Brit!
To reduce the strain on the cylinder head gasket the pistons intrude by about 5mm into the head, so as to cover the gasket area at top dead centre where pressure and temperature are highest. The gasket is made of a spring steel recessed in a groove in the upper flange of the cylinder. The head is machined accordingly
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Re: 0 deck, any power to be had?
[Re: dvw]
#878681
12/17/10 10:26 PM
12/17/10 10:26 PM
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Joined: Jan 2003
Posts: 6,591
Canton, Ohio
Sport440
master
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master
Joined: Jan 2003
Posts: 6,591
Canton, Ohio
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Quote:
OK lets add this question. Aluminum rods need more piston to head. This has been discussed before. It varies with the type of rod,weight ,RPM,etc. Lets say the combo requires .060" piston to head. How much quench distance is there while the engine is running? If the piston touches the head at .057" do I have effective quench?
Doug
Absolutely, Why wouldnt it? 
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Re: 0 deck, any power to be had?
[Re: Sport440]
#878682
12/17/10 11:11 PM
12/17/10 11:11 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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Another source of miniscule power "loss" would be the dead space above the top ring. With a piaton below deck, the ring is down further in the bore (assuming identical ring placement on the two comparable engines' pistons) and that will allow air/fuel to be trapped there and not burn. I routinely run pistons at .005" above deck, mainly because I want .030-.035" quench distance with the Felpro .039 gaskets. You also want to minimize the chamfer on the top of the bore as this too can work as "dead volume".
On the aluminum option, you have to maintain some distance between the piston and head, but some of the fastest engines I know of just touch at very high rpms. Just enough to leave a mark. The less "dead space" you have in the chamber the more mixture gets burnt completely and more power is realized.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: 0 deck, any power to be had?
[Re: Sport440]
#878683
12/18/10 12:07 AM
12/18/10 12:07 AM
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Joined: Jan 2007
Posts: 3,695
nc
emarine01
master
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master
Joined: Jan 2007
Posts: 3,695
nc
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Quote:
Quote:
OK lets add this question. Aluminum rods need more piston to head. This has been discussed before. It varies with the type of rod,weight ,RPM,etc. Lets say the combo requires .060" piston to head. How much quench distance is there while the engine is running? If the piston touches the head at .057" do I have effective quench?
Doug
Absolutely, Why wouldnt it?
Heat soak with alu rods before you make a pass and the quench should be close to a steel rod engine, most alu rods need hot oil before you load them up anyway
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Re: 0 deck, any power to be had?
[Re: emarine01]
#878684
12/18/10 02:00 PM
12/18/10 02:00 PM
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Joined: Feb 2003
Posts: 12,675
Columbia, CT
moper
I Live Here
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I Live Here
Joined: Feb 2003
Posts: 12,675
Columbia, CT
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I'm not way into aluminum rods but from what I know they are very elastic and they will stretch as the piston changes direction at TDC.. They do grow in length (and in term compress) while running hard even after reaching operating temp. The temp thing is more about stabilizing the oil temp and it's ability to do it's job.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: 0 deck, any power to be had?
[Re: Tiger Core]
#878685
12/18/10 09:26 PM
12/18/10 09:26 PM
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Joined: Dec 2008
Posts: 1,200
UK
602heavy
pro stock
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pro stock
Joined: Dec 2008
Posts: 1,200
UK
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Re: 0 deck, any power to be had?
[Re: 602heavy]
#878686
12/18/10 10:11 PM
12/18/10 10:11 PM
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Joined: Oct 2010
Posts: 9
California, USA
Tiger Core
member
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member
Joined: Oct 2010
Posts: 9
California, USA
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Quote:
Quote:
Quote:
Thanks for posting Tiger , some interesting reading there.
Can you explain some more regards piston 5mm above deck & effect on head gasket? , are you saying the piston acts as a shroud of some sort?
Thanks again.
Hello fellow Brit!
To reduce the strain on the cylinder head gasket the pistons intrude by about 5mm into the head, so as to cover the gasket area at top dead centre where pressure and temperature are highest. The gasket is made of a spring steel recessed in a groove in the upper flange of the cylinder. The head is machined accordingly
Thanks.
Some guys on here would'nt have bothered answering seeing as i come from little ole UK.  , or they got us on 'ignore this user' 
I wouldn't worry too much. Most Americans treat Brits extra special- specially the ladies. Those blokes that don't  are usually bitter that we're nicking all their women and I'm ok with that  
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